Insect trap

ABSTRACT

An insect trap comprises an outer casing ( 3 ) having an opening, a light source ( 2 ), and a cover ( 1   c ) substantially closing the opening of the casing. The cover ( 1   c ) tapers from a first cross-section which matches that of the opening of the outer casing to a second cross-section which defines an insect entry port ( 4 ) leading into a chamber ( 5 ). The cover ( 1   c ) is made of a material that is substantially transparent to light having the frequency of the light source ( 2 ), and the light source is positioned so as to be visible from the open end of the outer casing ( 3 ) through the cover.

The present invention relates to a trap for insects which are attractedby light.

Insects are a nuisance, and in many cases a health hazard. Various meansare employed to kill them. A common method is to use ultraviolet lightto attract insects to a high voltage electrocution grid, or to anadhesive trapping board. Electrocution grids and their associatedelectrical components involve a high capital cost, while adhesive boardshave a limited effective life, are expensive and need to be replacedfrequently.

The aim of the invention is to provide a trap for insects which iseconomic to produce and maintain, and which does not suffer from thedisadvantages of known traps.

The present invention provides an insect trap comprising an outercasing, an inner casing and a source of electromagnetic radiation, theouter casing having an opening, the inner casing being mounted withinthe outer casing and having a back wall and a cover, the cover taperingfrom a first cross-section which matches hat of the opening of the outercasing to a second cross-section which defines an insect entry portleading into a chamber defined, at least partially, by the internalsurfaces of the back wall and the cover, at least the back wall and thecover being made of a material that is substantially transparent toelectromagnetic radiation having the frequency of the source, and thesource being positioned within the outer casing outside the chamber soas to be visible from the open end of the outer casing through thecover.

In a preferred embodiment, the inner casing further comprises side wallmeans connected to the cover at its first cross-section and to the backwall, the chamber being defined by the internal surfaces of the backwall, the cover and the side wall means. In this case, the outer casingmay have a closed end opposite to its opening, and the inner casing mayhave a cross-section which complements that of the outer casing in sucha manner that the inner casing is a close fit within the outer casing atleast at the opening of the outer casing, the cover tapering towards theback wall of the inner casing, and the back wall of the inner casingbeing positioned adjacent to the closed end of the outer casing.Advantageously, the source is positioned between the back wall and theclosed end of the outer casing.

Preferably, the cover is integrally formed with the back wall and theside wall means.

The source may be a light source, preferably an ultraviolet lightsource.

The outer casing conveniently has a generally square cross-section, andthe cover takes the form of a square-based pyramid. In this case, theentry port is substantially square.

Alternatively, the outer casing has a substantially rectangularcross-section, and the cover is frustoconical, or the outer casing hasan irregular shape, and the cover is frustoconical. In any of thesecases, the entry port may be substantially rectangular, circular orelliptical.

In another alternative, the entry port may take the form of an elongateopening defined by angled portions of the cover and the internal sidewall means.

Advantageously, the outer casing is made of a material that issubstantially opaque to electromagnetic radiation having the frequencyof the source, and the cover and the base of the inner casing are madeof a plastics material (preferably an acrylic plastics material)transparent to electromagnetic radiation having the frequency of thesource.

In another arrangement, the outer casing is generally cylindrical inconfiguration, having an annular opening in its cylindrical side wall,the annular opening defining the opening of the outer casing, the innercasing having a tubular compartment, an annular top wall and an annularbottom wall, and the cover being constituted by a pair of frustoconicalcover plates which converge towards one another to define an annularentry port which surrounds the tubular compartment, and wherein thesource is positioned within the tubular compartment.

In this case, the trap may be of modular construction, having aplurality of trap portions. Preferably, the trap has four portions, eachhaving the cross-section of a quadrant of a circle.

In a preferred embodiment, the insect trap further comprises means fordeterring insects from leaving the chamber via the entry port, thedeterrent means being positioned within the inner casing adjacent to theentry port. Preferably, the deterrent means is constituted by aplurality of substantially parallel electrodes, adjacent electrodesbeing of opposite polarity, and the electrodes being spaced apart insuch a manner that insects of species commonly regarded as pests cansimultaneously touch at least two electrodes of opposite polarity.

Advantageously, the electrodes are spaced apart by a distance lyingwithin the range of from 0.5 mm to 2.5 mm, and preferably the electrodespacing is substantially 1 mm. Also, the width of each of the electrodesmay lie within the range of from 0.5 mm to 2.5 mm, and preferably thewidth of each electrode is substantially 1 mm.

Conveniently, the electrodes are provided with means for connection toan alternating current mains supply.

The trap may further comprise current limiting means for limiting thecurrent supplied to the electrodes. Preferably, the current limitingmeans is such that insects that contact the deterrent means are stunnedor disoriented.

Several forms of insect trap, each of which is constructed in accordancewith the invention, will now be described in greater detail, by way ofexample, with reference to the drawings, in which:

FIG. 1 is a schematic sectional side view of the first form of insecttrap;

FIG. 2 is a perspective view of a trapping chamber forming part of thetrap of FIG. 1;

FIG. 3 is a schematic representation, on an enlarged scale, of astunning grid which can be incorporated within the trap of FIG. 1;

FIG. 4 is a schematic sectional side view of the second form of insecttrap;

FIG. 5 is a schematic representation, on an enlarged scale, of astunning grid which can be incorporated within the trap of FIG. 4;

FIG. 6a is a schematic side elevation of the third form of insect trap;

FIG. 6b is a schematic front elevation of the insect trap of FIG. 6a;

FIG. 7a is a schematic side elevation of the fourth form of insect trap;

FIG. 7b is a schematic front elevation of the insect trap of FIG. 7a;

FIG. 8 is a schematic side elevation of the fifth form of insect trap;and

FIG. 9 is a plan view of a modified version of the insect trap of FIG.8.

Referring to the drawings, FIG. 1 shows the first form of insect trapwhich has an inner casing 1 and an ultraviolet light source 2 mountedwithin an outer casing 3. The ultraviolet light source 2 is constitutedby a pair of ultraviolet fluorescent tubes. The tubes are mains powered,and are provided with conventional connection means (not shown) forelectrical connection to the mains. The outer casing 3 is generallycubical having an open end 3 a and a closed end 3 b at the opposite end.The inner casing 1 is made of a material, such as an acrylic, which istransparent to ultraviolet light, and the outer casing 3 is made of amaterial such as ABS which is opaque to ultraviolet light. The acrylicmaterial is not only transparent to ultraviolet light, but is alsoresistant to ultraviolet, that is to say it is resistant to degradationby ultraviolet light. The inner casing 1 is generally cuboidal having aback wall 1 a, side walls 1 b and a cover 1 c generally in the form of asquare-based pyramid with an open base. The narrow end of thepyramid-shaped cover 1 c is open to define an entry port 4. The internalsurfaces of the back wall 1 a, the side walls 1 b and the cover 1 cdefine a chamber 5 which constitutes a receptacle for holding trappedinsects. The ultraviolet source 2 is positioned between the back wall 1a of the inner casing and the closed end 3 b of the outer casing 3

In use, the ultraviolet light source 2 attracts insects to the trap andinto the chamber 5 via the narrow entry port 4. Once in the chamber 5,insects find it difficult to escape via the narrow port 4. Althoughtrapped insects will eventually die inside the chamber 5, means arepreferably provided to deter trapped insects from happening upon theport 4 and escaping. Preferably, the deterrent means is an electrifiedstunning grid 6 positioned within the chamber 5 adjacent to the port 4.Means may also be provided to accelerate the dying process. For example,a renewable desiccant can be provided within the chamber 5, thedesiccant being effective to accelerate dehydration of trapped insects,thereby accelerating their death.

The grid 6 is constituted by four grid sections, each of which isattached to one of the four tapering walls defining the cover 1 c. Eachof the grid sections (one of which is shown in FIG. 3) is constituted bya series of parallel, adjacent electrodes 7 and 8 of oppositepolarities. The electrodes 7 are electrically connected by means of afirst base plate (not shown), and the electrodes 8 are electricallyconnected by means of a second base plate (not shown). The electrodes 7and 8 are connectable to the mains by means of contacts (not shown). Themains voltage may be any normal mains voltage such as 100 volts or 240volts, alternating at normal frequencies such as 50 Hz to 60 Hz.Preferably, the current applied to the grid 6 is limited by means of asuitable current-limiting device (not shown) which limits the current toan appropriate value (for example 5 mA). The electrodes 7 and 8 aresized and spaced so that insects of species commonly regarded as pestswill simultaneously touch at least a pair of electrodes 7 and 8 ofopposite polarity, on coming into contact with the grid 6. Typically,the electrodes 7 and 8 have a width of 1 mm, and a spacing of 1 mm.

The electrodes 7 and 8 are made of a suitable metal, such as stainlesssteel and may be supported by a non-conducting substrate made of, forexample, fibreglass. Alternatively, the electrodes 7 and 8 could bedeposited onto the cover 1 c, for example by electrodeposition. Beingmade of stainless steel the electrodes 7 and 8 are resistant tooxidation, and to degradation from the effects of humidity and/orchemicals from the trapped insects.

This simple grid 6 has a distressing affect on insects, which findcontact with it unsustainable. They either fly or leap off in a state ofdisorganisation or fall to the floor of the trap, temporarily stunned.Contact with the grid 6 causes damage, and repeated contact will have acumulative effect, leading to accelerated death. As the grid 6 is sitedround the port 4, random escape is prevented by deterring access to thenarrow mouth of the port.

FIG. 4 shows the second form of insect trap. This trap is a modifiedversion of the trap of FIGS. 1 to 3, so like reference numerals will beused for like parts, and only the modifications will be described indetail. This trap differs from that of FIGS. 1 to 3 in that the port isfined by generally triangular-shape flanges 4 a formed at the inner endsof the four tapering walls defining the cover 1 c, and by a modifiedform of grid 6′ (see FIG. 5). The grid 6 has a pair of electrodes 7′ and8′ opposite polarities, each of the electrodes being in the form of a“square spiral”. The grid 6′ is in one plane rather than in the planesof each of the four tapering walls defining the cover 1 c. The grid 6′is fixed to the flanges 4 a. so as to surround the port 4. Theelectrodes 7′ and 8′ are connected to the mains by means of contacts(not shown).

The second form of insect trap operates in the same way as the firstform of insect trap.

FIGS. 6a and 6 b show the third form of insect trap. This trap is also amodified version of the trap of FIGS. 1 to 3, so like reference numeralswill be used for like parts, and only the modifications will bedescribed in detail. This trap differs from that of FIGS. 1 to 3 in thatthe out and the inner casing 1 are asymmetrical, the outer casing havinga lower front wall 3 d that has a greater height than its upper frontwall 3 e. Similarly, the inner casing 1 has a lower front wall 1 d,which contrasts with the upper front end 1 e of the inner casing whichis pointed. The outer casing lower front wall 3 d covers the innercasing lower wall 1 d. One advantage of this arrangement is that thelower portion of the chamber 5 defined by the inner casing 1 is largerthan that of the trap of FIGS. 1 to 3, and so can hold a larger numberof dead insects. The grid 6 of this trap is identical to that of thetrap of FIGS. 1 to 3.

The fourth form of trap, shown in FIGS. 7a and 7 b, is identical to thatof FIGS. 6a and 6 b except that the inner casing 1 is not frustoconical,having a cover 1′c defined by a pair of walls which are angledrespectively from the edge of the upper side wall 1 b and from the upperedge of the lower front wall 1 d to an elongate entry port 4′ defined bythe horizontal ends of the angled walls of the cover and the side wallsof the outer casing 1. In this case, there are two grids 6 fixed to thefree ends of the angled wall adjacent to the entry port 4′. Each grid 6is constituted by a modified elongate version of the grid section shownin FIG. 3. Two further grids (not shown) are fixed to the side walls 1 bimmediately inside the chamber 5 and adjacent to the entry port 4′.

The trap of FIG. 8 has an inner casing 11 and an ultraviolet source 12mounted within an outer casing 13. The outer casing 13 is generallycylindrical, having an annular opening 13 a which extends over the majorportion of its cylindrical side wall. The inner casing 11 is ofgenerally cylindrical configuration, and includes a generally tubularannular compartment 11 a, a generally annular top wall 11 b, a generallyannular bottom wall 11 c, and a pair of cover plates 11 d and 11 e, eachof frustoconical configuration. The cover plate 11 d is angleddownwardly and inwardly from the top wall 11 b, and the cover plate 11 eis angled upwardly and inwardly from a lower front wall 11 f. The freeends of the two cover plates 11 d and 11 e thus form an annular entryport 14 which surrounds the compartment 11 a. The ultraviolet lightsource 12, which is constituted by a single tube, is positioned withinthe tubular compartment 11 a. A respective grid 16 is positioned ontriangular-shaped flanges 14 a formed at the inner ends of the twoconical cover plates 11 d and 11 e,and adjacent to the entry port 14.Each grid 16 is constituted by a plurality (typically six) of parallelelectrodes, each of which is of annular configuration. As with the grid6 of FIGS. 1 to 3, adjacent electrodes are of opposite polarity, and theelectrodes of each polarity are connected to one another and to arespective mains terminal.

As with the earlier embodiments, the inner casing 11 is made of anacrylic which is transparent to ultraviolet light, and the outer casing13 is made of ABS which is opaque to ultraviolet light.

This trap operates in the same manner, and has similar advantages to,the first four forms of trap.

This trap can be of modular construction, as shown in FIG. 9, whichshows the trap formed from four quadrants A, B, C and D, and with fourultraviolet light sources 12, each of which is positioned in arespective quadrant-shaped channel at the “apex” of the associatedquadrant. The trap could be used in this configuration, or it couldconsist of one, two or three of the quadrants. For example, where a trapis to be positioned in the corner of a room it could have only onetrapping chamber quadrant.

The insect traps described above have considerable advantages over knowntraps. They are cheaper to manufacture and more effective than knowelectrocuting insect traps, and cheaper to run than traps utilizingreplaceable adhesive boards. They are also more effective than knowntraps, in that they retain all the insects they attract—electrocutinginsect traps only work with larger insects, and adhesive board trapsonly trap a proportion of the insects attracted. Unlike electrocuteinsect traps, the traps described above do not eject fragments oftrapped and killed insects, and so are suitable for use in the proximityof food. Another advantage of these traps is that the ultraviolettube(s) are enclosed, so that the need for expensive shatter proofing(which is required with some known traps when used in the vicinity offood) is avoided

It will be apparent that modifications could be made to the trapsdescribed above. Thus, the ultraviolet light sources 2 or 12 could bereplaced by different light sources, though ultraviolet light ispreferred as it is more attractive to insects. In this case, the innercasing 1 or 11 would be made of a material transparent to light of theappropriate frequency, and the outer casing 3 or 13 would be made of amaterial opaque to light of that frequency. The cover 1 c could be ofany frustoconical shape, and could be regular, irregular or asymmetricin cross-section. It would also be possible to position the light source2 or 12 outside the casing 3 or 13, and to provide means for conductinglight to the back wall 1 a or to the compartment 11 a so as to shinethrough that member and through the cover 1 c or the cover plates 11 dand 11 e. It would, of course, be possible to use a single ultraviolettube, or two or more such tubes, as the ultraviolet source.

The grid 6, 6′ or 16 could also be electrified with any voltage at whichcurrent may pass through an insect at a sufficient level todisorientate, damage or otherwise discourage it from remaining on thegrid. Similarly, frequencies other than those normally used for a mainssupply could be used. It would also be possible to use alternatingcurrents having waveforms other than sinusoidal. Direct current orpulsed direct current could also be used, though steady direct currentmay be less effective, in that it may cause insects to stick to the grid6, 6′ or 16, rather than be jolted off or leap/fly away. This could clogthe grid 6, 6′ or 16, and lead to the possibility of a carbonised linkcreating a short circuit. Direct current would, therefore, lead to theneed for the grid 6, 6′ or 16 to be cleaned frequently.

It would also be possible to provide that portion of the outer casing 3or 13 adjacent to the light source(s) 2 or 12 with ventilation holes forcooling the light source(s) and the body of the trap. Such ventilationholes would be provided with baffles to prevent the light source(s) 2 or12 from being seen from outside the trap through the ventilation holes.The inner casing 1 or 11 and the outer casing 3 or 13 could be ofmodular construction, thereby permitting traps of different sizes to bemade from a small number of basic components. A removable tray forfacilitating the removal of dead insects could be provided.Alternatively, a door or a removable portion of the inner casing 1 or 11may facilitate this. The easy removability of the inner casing 1 or 11from the outer casing 3 or 13 facilitates access to the interior of thetrap for cleaning purposes. Another possibility would be to make theinner casing 1 or 11 from a disposable material such as paper which isat least partially transparent to light having the frequency of thelight source.

In a further embodiment (not shown), the inner casing 1 could beconstituted simply by the cover 1 c and the back wall 1 a. In this case,the cover would be fixed within the open end 3 a of the outer casing 3,and the chamber 5 would be defined by the internal surfaces of the cover1 c, the back wall 1 a and the side walls of the outer casing 3.

Also, the electrodes 7 and 8 could be made of a non-metallic conductorsuch as carbon. Finally, the grid 6, 6′ or 16 could be replaced, orsupplemented, by the use of a renewable desiccant or other means foraccelerating the death of trapped insects such as heat, infraredradiation or an appropriate electromagnetic field for affecting thenervous system of the insects. If a heat source is used, care must betaken that it is not too intense as to raise the temperature of the trapitself to an undesirable extent.

What is claimed is:
 1. An insect trap comprising an outer casing, aninner casing and a source of electromagnetic radiation, the outer casinghaving an opening, the inner casing being mounted within the outercasing and having a back wall and a cover, the cover tapering from afirst cross-section which matches that of the opening of the outercasing to a second cross-section which defines an insect entry portleading into a an insect trapping chamber defined, at least partially,by the internal surfaces of the back wall and the cover, at least theback wall and the cover being made of a material that is substantiallytransparent to electromagnetic radiation having the frequency of thesource, and the source being positioned within the outer casing outsidethe chamber so as to be visible from the open end of the outer casingthrough the cover.
 2. An insect trap as claimed in claim 1, wherein theinner casing further comprises side wall means connected to the cover atits first cross-section and to the back wall, the chamber being definedby the internal surfaces of the back wall, the cover and the side wallmeans.
 3. An insect trap as claimed in claim 2, wherein the outer casinghas a closed end opposite to its opening, and the inner casing has across-section which complements that of the outer casing in such amanner that the inner casing is a close fit within the outer casing atleast at the opening of the outer casing, the cover tapering towards theback wall of the inner casing, and the back wall of the inner casingbeing positioned adjacent to the closed end of the outer casing.
 4. Aninsect trap as claimed in claim 3, wherein the source is positionedbetween the back wall of the inner casing and the closed end of theouter casing.
 5. An insect trap as claimed in claim 3, wherein the coveris integrally formed with the back wall and the side wall means.
 6. Aninsect trap as claimed in claim 1, wherein the source is a light source.7. An insect trap as claimed in claim 1, wherein the source is anultraviolet light source.
 8. An insect trap as claimed in claim 1,wherein the outer casing has a generally square cross-section, and thecover takes the form of a square-based pyramid.
 9. An insect trap asclaimed in claim 8, wherein the entry port is substantially square. 10.An insect trap as claimed in claim 1, wherein the outer casing has asubstantially rectangular cross-section, and the cover is frustoconical.11. An insect trap as claimed in claim 1, wherein the outer casing hasan irregular shape, and the cover is frustoconical.
 12. An insect trapas claimed in claim 1, wherein the entry port is substantiallyrectangular, circular or elliptical.
 13. An insect trap as claimed inclaim 1, wherein the entry port takes the form of an elongate openingdefined by angled portions of the cover and internal side wall means.14. An insect trap as claimed in claim 1, wherein the outer casing ismade of a material that is substantially opaque to electromagneticradiation having the frequency of the source.
 15. An insect trap asclaimed in claim 1, wherein the cover and the back wall of the innercasing are made of a plastics material transparent to electromagneticradiation having the frequency of the source.
 16. An insect trap asclaimed in claim 1, wherein the cover and the back wall of the innercasing are made of an acrylic plastics material transparent toelectromagnetic radiation having the frequency of the source.
 17. Aninsect trap as claimed in claim 1, wherein the outer casing is generallycylindrical in configuration, having an annular opening in itscylindrical side wall, the annular opening defining the opening of theouter casing, the inner casing having a tubular compartment, an annulartop wall and an annular bottom wall, and the cover being constituted bya pair of frustoconical cover plates which converge towards one anotherto define an annular entry port which surrounds the tubular compartment,and wherein the source is positioned within the tubular compartment. 18.An insect trap as claimed in claim 17, wherein the trap is of modularconstruction, having a plurality of trap portions.
 19. An insect trap asclaimed in claim 18, wherein the trap has four portions, each having thecross-section of a quadrant of a circle.
 20. An insect trap as claimedin claim 1, further comprising means for deterring insects from leavingthe chamber via the entry port, the deterrent means being positionedwithin the inner casing adjacent to the entry port.
 21. An insect trapas claimed in claim 20, wherein the deterrent means is constituted by aplurality of substantially parallel electrodes, adjacent electrodesbeing of opposite polarity, and the electrodes being spaced apart insuch a manner that insects of species commonly regarded as pests cansimultaneously touch at least two electrodes of opposite polarity, theelectrodes being positioned within the enclosure, or inner surfaces ofthe tapering wall adjacent to the insect entry opening.
 22. An insecttrap as claimed in claim 21, wherein the electrodes are spaced apart bya distance lying within the range of from 0.5 mm to 2.5 mm.
 23. Aninsect trap as claimed in claim 22, wherein the electrode spacing issubstantially 1 mm.
 24. An insect trap as claimed in claim 21, whereinthe width of each of the electrodes lies within the range of from 0.5 mmto 2.5 mm.
 25. An insect trap as claimed in claim 24, wherein the widthof each of the electrodes is substantially 1 mm.
 26. An insect trap asclaimed in claim 21, wherein the electrodes are provided with means forconnection to an alternating current mains supply.
 27. An insect trap asclaimed in claim 26, further comprising current limiting means forlimiting the current supplied to the electrodes.
 28. An insect trap asclaimed in claim 27, wherein the current limiting means is such thatinsects that contact the deterrent means are stunned or disorientated.29. An insect trap as claimed in claim 20, wherein the enclosure isdefined by an outer casing and an inner casing, the inner casing beingmounted within the outer casing and having a back wall opposite thetapering wall, the cover tapering from a first cross-section whichmatches that of the opening of the outer casing to a secondcross-section to define the insect entry port, at least the back walland the cover of the inner casing being made of a material that issubstantially transparent to electromagnetic radiation having thefrequency of the source, and the source being positioned within theouter casing, and outside the inner casing, so as to be visible from theopen end of the outer casing through the cover.
 30. An insect trap asclaimed in claim 29, wherein the source is an ultraviolet light source.31. An insect trap comprising an outer casing, an inner casing and asource of electromagnetic radiation, the outer casing having an opening,the inner casing being mounted within the outer casing and having a backwall and a cover, the cover tapering from a first cross-section whichmatches that of the opening of the outer casing to a secondcross-section which defines an insect entry port leading into a chamberdefined, at least partially, by the internal surfaces of the back walland the cover, the back wall being substantially planar and positionedto face the insect entry port, at least the back wall and the coverbeing made of a material that is substantially transparent toelectromagnetic radiation having the frequency of the source, and thesource being positioned within the outer casing outside the chamber soas to be visible from the open end of the outer casing through thecover.